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本文研究了经1300℃氧化处理的Fe-25Cr-5Al合金中微量铈和镧的分布,认为在合金氧化过程中,基体内的铈将向基体/氧化皮界面附近的区域扩散,并产生内氧化,而形成铈的内氧化质点密集区;随着氧化时间的延长,铈内氧化质点的密集程度和密集区的宽度均不断增大。镧的行为与铈相似,但密集速度相对比较慢,且内氧化质点也较少。铈和镧的内氧化质点的密集,将导致合金表面层的弥散强化,提高合金表面层抗塑性变形能力,从而阻止卷旋氧化皮形貌的发展,改善氧化皮的粘附性。此外,铈和镧的内氧化将降低合金表面层的氧分压,使铁和铬难以发生内氧化和进入氧化皮,这将有利于改善α-Al_2O_3氧化皮的结合力。
In this paper, the distribution of trace amounts of cerium and lanthanum in Fe-25Cr-5Al alloy treated by oxidation at 1300 ℃ is studied. It is considered that during the oxidation of the alloy, cerium in the matrix will diffuse to the vicinity of the matrix / scale interface and generate internal oxidation , While the formation of dense spots of the inner oxide particles of cerium. With the extension of the oxidation time, the density of the oxidized particles in the cerium and the width of the dense area are continuously increasing. The behavior of lanthanum is similar to that of cerium, but the relative density is relatively slow, and there are fewer internal oxidized particles. The dense internal oxide grains of cerium and lanthanum will lead to the dispersion strengthening of the surface layer of the alloy and improve the plastic deformation resistance of the alloy surface layer, thereby preventing the development of the rolled oxide surface and improving the adhesion of the scale. In addition, the internal oxidation of cerium and lanthanum will reduce the oxygen partial pressure of the alloy surface layer, so that iron and chromium are difficult to internal oxidation and into the scale, which will help improve the adhesion of α-Al 2 O 3 scale.